feat: add recipe translation tool with AI translation and settings management

- Add Word document parsing and translation export
- Add database configuration management
- Add AI/LLM translation configuration
- Add translation vocabulary management
- Add export settings (colors, page orientation, headers)
- Separate database and AI configurations
- Add debounced search to prevent database overload

lib/config.ts

@@ -0,0 +1,173 @@
+import fs from "fs";
+import path from "path";
+
+export interface DBConfig {
+  host: string;
+  port: number;
+  user: string;
+  password: string;
+  database: string;
+}
+
+export interface AIConfig {
+  apiKey: string;
+  baseUrl: string;
+  model: string;
+}
+
+export interface AppConfig {
+  db: DBConfig;
+  ai: AIConfig;
+}
+
+// 配置文件路径（单一文件）
+const configPath = path.join(process.cwd(), "config.json");
+
+/**
+ * 读取完整配置
+ */
+function readConfigFile(): Partial<AppConfig> {
+  try {
+    if (fs.existsSync(configPath)) {
+      const content = fs.readFileSync(configPath, "utf-8");
+      return JSON.parse(content);
+    }
+  } catch (e) {
+    console.error("Config read error:", e);
+  }
+  return {};
+}
+
+/**
+ * 写入完整配置
+ */
+function writeConfigFile(config: AppConfig): void {
+  fs.writeFileSync(configPath, JSON.stringify(config, null, 2), "utf-8");
+}
+
+/**
+ * 获取数据库配置
+ * 优先级：环境变量 > config.json
+ */
+export function getDBConfig(): DBConfig {
+  let host = "127.0.0.1";
+  let port = 3306;
+  let user = "root";
+  let password = "";
+  let database = "recipe_tools";
+
+  // 环境变量优先级最高
+  if (process.env.DB_HOST) host = process.env.DB_HOST;
+  if (process.env.DB_PORT) port = parseInt(process.env.DB_PORT);
+  if (process.env.DB_USER) user = process.env.DB_USER;
+  if (process.env.DB_PASSWORD) password = process.env.DB_PASSWORD;
+  if (process.env.DB_NAME) database = process.env.DB_NAME;
+
+  // config.json 次之（仅当环境变量未设置时）
+  const fileConfig = readConfigFile();
+  if (fileConfig.db) {
+    if (fileConfig.db.host && !process.env.DB_HOST) host = fileConfig.db.host;
+    if (fileConfig.db.port && !process.env.DB_PORT) port = fileConfig.db.port;
+    if (fileConfig.db.user && !process.env.DB_USER) user = fileConfig.db.user;
+    if (fileConfig.db.password && !process.env.DB_PASSWORD) password = fileConfig.db.password;
+    if (fileConfig.db.database && !process.env.DB_NAME) database = fileConfig.db.database;
+  }
+
+  return { host, port, user, password, database };
+}
+
+/**
+ * 获取AI翻译配置
+ * 优先级：环境变量 > config.json
+ */
+export function getAIConfig(): AIConfig {
+  let apiKey = "";
+  let baseUrl = "https://api.openai.com/v1";
+  let model = "gpt-3.5-turbo";
+
+  // 环境变量优先级最高
+  if (process.env.AI_API_KEY) apiKey = process.env.AI_API_KEY;
+  if (process.env.AI_BASE_URL) baseUrl = process.env.AI_BASE_URL;
+  if (process.env.AI_MODEL) model = process.env.AI_MODEL;
+
+  // config.json 次之（仅当环境变量未设置时）
+  const fileConfig = readConfigFile();
+  if (fileConfig.ai) {
+    if (fileConfig.ai.apiKey && !process.env.AI_API_KEY) apiKey = fileConfig.ai.apiKey;
+    if (fileConfig.ai.baseUrl && !process.env.AI_BASE_URL) baseUrl = fileConfig.ai.baseUrl;
+    if (fileConfig.ai.model && !process.env.AI_MODEL) model = fileConfig.ai.model;
+  }
+
+  return { apiKey, baseUrl, model };
+}
+
+/**
+ * 获取完整配置（兼容旧接口）
+ */
+export function getConfig(): AppConfig {
+  return {
+    db: getDBConfig(),
+    ai: getAIConfig(),
+  };
+}
+
+/**
+ * 保存数据库配置
+ */
+export function saveDBConfig(config: Partial<DBConfig>): DBConfig {
+  const current = getDBConfig();
+
+  const newConfig: DBConfig = {
+    host: config.host ?? current.host,
+    port: config.port ?? current.port,
+    user: config.user ?? current.user,
+    password: config.password ?? current.password,
+    database: config.database ?? current.database,
+  };
+
+  // 读取现有配置，更新 db 部分
+  const fileConfig = readConfigFile();
+  const updatedConfig: AppConfig = {
+    ai: fileConfig.ai ?? { apiKey: "", baseUrl: "https://api.openai.com/v1", model: "gpt-3.5-turbo" },
+    db: newConfig,
+  };
+  writeConfigFile(updatedConfig);
+
+  return newConfig;
+}
+
+/**
+ * 保存AI翻译配置
+ */
+export function saveAIConfig(config: Partial<AIConfig>): AIConfig {
+  const current = getAIConfig();
+
+  const newConfig: AIConfig = {
+    apiKey: config.apiKey ?? current.apiKey,
+    baseUrl: config.baseUrl ?? current.baseUrl,
+    model: config.model ?? current.model,
+  };
+
+  // 读取现有配置，更新 ai 部分
+  const fileConfig = readConfigFile();
+  const updatedConfig: AppConfig = {
+    db: fileConfig.db ?? { host: "127.0.0.1", port: 3306, user: "root", password: "", database: "recipe_tools" },
+    ai: newConfig,
+  };
+  writeConfigFile(updatedConfig);
+
+  return newConfig;
+}
+
+/**
+ * 保存完整配置（兼容旧接口）
+ */
+export function saveConfig(config: Partial<AppConfig>): AppConfig {
+  const current = getConfig();
+  const fileConfig = readConfigFile();
+
+  return {
+    db: config.db ? saveDBConfig(config.db) : current.db,
+    ai: config.ai ? saveAIConfig(config.ai) : current.ai,
+  };
+}